Bim Afolami is MP for Hitchin & Harpenden.

Lyndon Johnson is said to have remarked, after signing the US Civil Rights Bill of 1964, that the Democrats had “lost the South for a generation”. And so it proved.

From the late 1870s to the mid-1960s, the conservative whites of the Deep South held control of state governments, and overwhelmingly identified with and supported the Democratic Party

Meanwhile, the Republicans had significant strength in the North East and in the West (for example, in California – the home state of both Ronald Reagan and Richard Nixon).

Thirty years later, the Republicans held a majority of southern state governorships and seats in both houses of Congress, whilst liberal Republicans in the north east and west coast were becoming an endangered species (now largely extinct). Major realignments happen in politics.

In March 1962, the Liberal Party won a by-election in Orpington, a seemingly safe seat for the Conservatives, prosperous, suburban and on the edge of London, with a 22 per cent swing – resulting in a majority of almost 8,000.

The Conservative leadership was terrified by the result. In his diary of that night, Harold Macmillan noted that “we have been swept off our feet by the Liberal revival and made the world safe for Liberalism.” On election night, the newly-elected Liberal MP declared “There is not a safe Tory seat in the country.”

Does that result sound familiar? Yet, by the 1964 election, the Liberal Party only managed to increase its seats from six to nine, and by 1970 it was back down to six seats. Sometimes, the promised realignments do not occur.

After the terrible by-election result in Chesham and Amersham, southern Conservative MPs in Remain-leaning seats, particularly in the commuter belt, are wondering what the result means. In the run-up to election day, more and more of us started to feel that we might lose it.

But none of us thought it would be as bad as that. Some have been quick to proclaim doom for these sorts of seats as a Brexit corollary of the Conservative advance in the “red wall” in the North and Midlands. Other explanations are less ideological – and put the result down to planning reform first and foremost, or a need to have more focused and targeted messages for southern voters.

It is hard to know the truth, and having knocked on lots of doors it is my sense that all of these accounts have some truth to them. Yet in one sense it doesn’t actually matter what the explanation is. Rather: what is the impact on southern Tory MPs who hold these seats, and on their constituency associations and councillors?

The psychology of Conservatives in the Home Counties has changed profoundly as a result of this result, combined with relatively mediocre results in May’s local elections, in three principal ways.

First comes is the scary realisation that the electorate is more volatile now than since before Brexit. Voters are less attached to their party of choice, and are shopping around at each election more than ever before. Very little can be taken for granted if a seat with a comfortable 15,000 majority can be lost on a 25 per cent swing. The 2015 and 2017 elections demonstrated the highest voter volatility in British election history, with 2019 being the sixth highest.

Secondly, southern Conservatives have started to think of themselves as facing similar challenges, and are starting to share best practice on local campaigning and incumbency. In the past, MPs tended to think of themselves as those who were either in a safe seat or in a marginal – and informal groupings tended to gather on that basis. Now, as the Party’s electoral fortunes look to be increasingly different in different parts of the country, these regional groupings tend to be more resonant.

Third, many southern Conservatives have decided that planning reform is the new “third rail” of politics – an issue that cannot be touched without causing immediate political death. The way that the Lib Dems cynically lied and exploited the issue in Chesham and Amersham has convinced many that doing anything at all will be a great political mistake on the scale of the Poll Tax. This is going to be an extremely difficult issue for the Government and the wider parliamentary party to crack, because we all know that the planning system is broken, and needs quite significant reform. Something must be done. This one will run and run.

Overall, southern MPs are feeling a little less comfortable, and that is not altogether a bad thing. As my former boss in the City used to repeat to me on a regular basis, only the paranoid survive! Undoubtedly, there will be more marginal seats in the south of England at the next election than we have recently been used to: we will be threatened by the Liberal Democrats, Labour, and the Greens, all aided by significant tactical voting.

When I look at the newer “Red Wall” MPs, I see campaigning acumen, vigour and toughness, borne out of several years having to fight extremely hard against an entrenched Labour Party. Combined with this raw campaigning toughness, many of these MPs are developing new ideas and expanding the Conservative base in their areas. There is a new, grittier, more northern conservatism that is pro-industrial economy, pro-worker, and pro-Green because of jobs and living standards: pro-low tax but not at the expense of public services.

Southern MPs need to engage more fully in the debate about the changing nature of conservatism. We should work together with our northern colleagues as one united parliamentary party and also not be afraid to champion ideas that will have real resonance in the south.

Good examples are Claire Coutinho of East Surrey) and David Johnstone of Wantage, who are working on a project with the Social Market Foundation on how to close the “Opportunity Gap”, which seeks to examine ideas on how to end inequality of opportunity. As we emerge from Covid 19, there is a huge debate to be had about the nature of the new British economy, how to deal with the generational divide between young and old, and the politics of net zero and the environment.

Many of these issues will be seen differently in Hitchin than Hartlepool: we must develop a policy framework that is flexible enough to embrace our broadened church and our incredibly varied country. The next election may well be fought very differently in different regions.

But this cannot be policy in a soulless, technocratic way. Policy without a philosophical underpinning never takes root properly. We need to recognise that the days of Cameroon hyper-liberalism (in both an economic and social sense) are gone. Nothing yet has yet taken its place. Let’s work with our northern colleagues to redefine Conservatism for the 21st century in a way that suits both north and south, leaver and remainer, young and old.